en>Pratyya Ghosh: Reverted 1 edit by 14.140.235.58 identified as test/vandalism using STiki

2014-09-16T13:19:48Z

Reverted 1 edit by 14.140.235.58 identified as test/vandalism using STiki

en>Zeusfaber: Correct name of Denny Tank and minor tidying up of language

2014-01-22T18:48:15Z

Correct name of Denny Tank and minor tidying up of language

← Older revision		Revision as of 20:48, 22 January 2014
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	~~Love is what my partner enjoys~~ to ~~phone me but I never like when people use my comprehensive identify~~. ~~To fence~~ is ~~one thing my partner does not truly like but I do. For~~ a ~~although I have been in New Hampshire but I need to move~~ for ~~my family members~~. ~~My job~~ is a [~~http://Search.Usa.gov/search?query=dispatcher dispatcher~~]. ~~I'm not very good at webdesign but you might want~~ to ~~examine my internet site: https://demos2.softaculous~~.~~com/MediaWiki/index.php/User:LatashiSeale<br><br>~~		{{More footnotes\|date=February 2010}}
			[[Image:Normal map example.png\|thumb\|350px\|Normal mapping used to re-detail simplified meshes.]]
			In [[3D computer graphics]], '''normal mapping''', or "Dot3 bump mapping", is a technique used for faking the lighting of bumps and dents - an implementation of [[Bump mapping]]. It is used to add details without using more [[polygonal modeling\|polygon]]s. A common use of this technique is to greatly enhance the appearance and details of a [[low poly\|low polygon model]] by generating a normal map from a high polygon model or height map.

	~~Also visit my page~~ ... ~~Asics Gel Cardio~~, [~~https~~://~~demos2~~.~~softaculous~~.com/~~MediaWiki~~/index.php/~~User~~:~~LatashiSeale softaculous~~.com],		Normal maps are commonly stored as regular [[RGB]] images where the RGB components corresponds to the X, Y, and Z coordinates, respectively, of the [[surface normal]].

			== History ==
			The idea of taking geometric details from a high polygon model was introduced in "Fitting Smooth Surfaces to Dense Polygon Meshes"
			by Krishnamurthy and Levoy, Proc. [[SIGGRAPH]] 1996,<ref>Krishnamurthy and Levoy, ''[http://www-graphics.stanford.edu/papers/surfacefitting/ Fitting Smooth Surfaces to Dense Polygon Meshes]'', SIGGRAPH 1996</ref> where this approach was used for creating [[displacement mapping\|displacement maps]] over [[nurbs]]. In 1998, two papers were presented with key ideas for transferring details with normal maps from high to low polygon meshes: "Appearance Preserving Simplification", by Cohen et al. SIGGRAPH 1998,<ref>Cohen et al., [http://www.cs.unc.edu/~geom/APS/APS.pdf Appearance-Preserving Simplification], SIGGRAPH 1998 '''(PDF)'''</ref> and "A general method for preserving attribute values on simplified meshes" by Cignoni et al. IEEE Visualization '98.<ref>Cignoni et al., [http://vcg.isti.cnr.it/publications/papers/rocchini.pdf A general method for preserving attribute values on simplified meshes], IEEE Visualization 1998 '''(PDF)'''</ref>
			The former introduced the idea of storing surface normals directly in a texture, rather than displacements, though it required the low-detail model to be generated by a particular constrained simplification algorithm. The latter presented a simpler approach that decouples the high and low polygonal mesh and allows the recreation of any attributes of the high-detail model (color, [[texture mapping\|texture coordinates]], [[displacement mapping\|displacements]], etc.) in a way that is not dependent on how the low-detail model was created. The combination of storing normals in a texture, with the more general creation process is still used by most currently available tools.

			==How it works==
			[[File:Normal map example with scene and result.png\|thumb\|upright=1.8\|Example of a normal map (center) with the scene it was calculated from (left) and the result when applied to a flat surface (right).]]
			To calculate the [[Lambertian]] (diffuse) lighting of a surface, the unit [[Vector (geometric)\|vector]] from the shading point to the light source is [[dot product\|dotted]] with the unit vector normal to that surface, and the result is the intensity of the light on that surface. Imagine a polygonal model of a sphere - you can only approximate the shape of the surface. By using a 3-channel bitmap textured across the model, more detailed normal vector information can be encoded. Each channel in the bitmap corresponds to a spatial dimension (X, Y and Z). These spatial dimensions are relative to a constant coordinate system for object-space normal maps, or to a smoothly varying coordinate system (based on the derivatives of position with respect to texture coordinates) in the case of tangent-space normal maps. This adds much more detail to the surface of a model, especially in conjunction with advanced lighting techniques.

			Since a normal will be used in the dot product calculation for the diffuse lighting computation, we can see that the {0, 0, –1} would be remapped to the {128, 128, 0} values, giving that kind of sky blue color seen in normal maps (blue (z) coordinate is perspective (deepness) coordinate and RG-xy flat coordinates on screen). {0.3, 0.4, –0.866} would be remapped to the ({0.3, 0.4, –0.866}/2+{0.5, 0.5, 0.5})255={0.15+0.5, 0.2+0.5, -0.433+0.5}255={0.65, 0.7, 0.067}*255={166, 179, 17} values (<math>0.3^2+0.4^2+(-0.866)^2=1</math>). Coordinate ''z'' (blue) minus sign flipped, because need match normal map normal vector with eye (viewpoint or camera) vector or light vector (because sign "-" for ''z'' axis means vertex is in front of camera and not behind camera; when light vector and normal vector match surface shined with maximum strength).

			==Calculating tangent space==
			{{Expand section\|more math\|date=October 2011}}
			In order to find the perturbation in the normal the tangent space must be correctly calculated.<ref>Mikkelsen, [http://image.diku.dk/projects/media/morten.mikkelsen.08.pdf Simulation of Wrinkled Surfaces Revisited], 2008 '''(PDF)'''</ref>
			Most often the normal is perturbed in a fragment shader after applying the model and view matrices.
			Typically the geometry provides a normal and tangent. The tangent is part of the tangent plane
			and can be transformed simply with the [[Affine transformation\|linear]] part of the matrix
			(the upper 3x3). However, the normal needs to be transformed by the [[Surface_normal#Transforming_normals\|inverse transpose]]. Most applications will want cotangent to
			match the transformed geometry (and associated uv's). So instead of enforcing the cotangent to
			be perpendicular to the tangent, it is generally preferable to transform the cotangent just like the
			tangent. Let ''t'' be tangent, ''b'' be cotangent, ''n'' be normal, ''M<sub>3x3</sub>'' be the linear part of model matrix, and ''V<sub>3x3</sub>'' be the linear part of the view matrix.
			:<math>t' = t \times M_{3x3} \times V_{3x3}</math>
			:<math>b' = b \times M_{3x3} \times V_{3x3}</math>
			:<math>n' = n \times (M_{3x3} \times V_{3x3})^{-1T} = n \times M_{3x3}^{-1T} \times V_{3x3}^{-1T}</math>

			==Normal mapping in video games==
			Interactive normal map rendering was originally only possible on [[PixelFlow]], a [[parallel rendering]] machine built at the [[University of North Carolina at Chapel Hill]].{{citation needed\|date=February 2012}} It was later possible to perform normal mapping on high-end [[Silicon Graphics\|SGI]] workstations using multi-pass rendering and [[framebuffer]] operations<ref>Heidrich and Seidel, [http://www.cs.ubc.ca/~heidrich/Papers/Siggraph.99.pdf Realistic, Hardware-accelerated Shading and Lighting], SIGGRAPH 1999 '''(PDF)'''</ref> or on low end PC hardware with some tricks using paletted textures. However, with the advent of [[shader]]s in personal computers and game consoles, normal mapping became widely used in commercial video games starting in late 2003. Normal mapping's popularity for [[real-time rendering]] is due to its good quality to processing requirements ratio versus other methods of producing similar effects. Much of this efficiency is made possible by distance-indexed detail scaling, a technique which selectively decreases the detail of the normal map of a given texture (cf. [[mipmapping]]), meaning that more distant surfaces require less complex lighting simulation.

			Basic normal mapping can be implemented in any hardware that supports palettized textures. The first game console to have specialized normal mapping hardware was the Sega [[Dreamcast]]. However, Microsoft's [[Xbox (console)\|Xbox]] was the first console to widely use the effect in retail games. Out of the [[History of video game consoles (sixth generation)\|sixth generation consoles]], only the [[PlayStation 2]]'s [[PlayStation 2#Technical specifications\|GPU]] lacks built-in normal mapping support. Games for the [[Xbox 360]] and the [[PlayStation 3]] rely heavily on normal mapping and are beginning to implement [[parallax mapping]]. The [[Nintendo 3DS]] has been shown to support normal mapping, as demonstrated by ''[[Resident Evil Revelations]]'' and ''[[Metal Gear Solid: Snake Eater#Metal Gear Solid 3: Snake Eater 3D\|Metal Gear Solid: Snake Eater]]''.

			==See also==
			* [[Texture mapping]]
			* [[Bump mapping]]
			* [[Parallax mapping]]
			* [[Displacement mapping]]
			* [[Reflection (physics)]]
			* [[Ambient occlusion]]
			* [[Depth map]]

			==References==
			{{reflist}}

			==External links==
			{{commons category}}
			<!-- This links seems to be dead: * [http://liman3d.com/tutorial_normalmaps.html Understanding Normal Maps] -->
			* [http://www.game-artist.net/forums/vbarticles.php?do=article&articleid=16 Introduction to Normal Mapping]
			* [http://wiki.blender.org/index.php/Manual/Bump_and_Normal_Maps Blender Normal Mapping]
			* [http://vcg.isti.cnr.it/activities/geometryegraphics/bumpmapping.html Normal Mapping with paletted textures] using old OpenGL extensions.
			* [http://zarria.net/nrmphoto/nrmphoto.html Normal Map Photography] Creating normal maps manually by layering digital photographs
			* [http://www.3dkingdoms.com/tutorial.htm Normal Mapping Explained]
			* [http://sourceforge.net/projects/simplenormalmapper Simple Normal Mapper] Open Source normal map generator

			[[Category:Demo effects]]
			[[Category:Texture mapping]]
			[[Category:Virtual reality]]

en>JYBot: r2.7.1) (Robot: Modifying ar:عدد فرود

2012-09-02T11:39:27Z

r2.7.1) (Robot: Modifying ar:عدد فرود

New page

Love is what my partner enjoys to phone me but I never like when people use my comprehensive identify. To fence is one thing my partner does not truly like but I do. For a although I have been in New Hampshire but I need to move for my family members. My job is a [http://Search.Usa.gov/search?query=dispatcher dispatcher]. I'm not very good at webdesign but you might want to examine my internet site: https://demos2.softaculous.com/MediaWiki/index.php/User:LatashiSeale<br><br>

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Froude number - Revision history

en>Pratyya Ghosh: Reverted 1 edit by 14.140.235.58 identified as test/vandalism using STiki

en>Zeusfaber: Correct name of Denny Tank and minor tidying up of language

en>JYBot: r2.7.1) (Robot: Modifying ar:عدد فرود